Refrigerant System (page 7 of 9)

AIR CONDITIONING

82-12

DESCRIPTION AND OPERATION

Thermostatic Expansion Valve (TXV)

1 High pressure (evaporator inlet) servicing 

connection

2 Low pressure (evaporator outlet) servicing 

connection

3 Thermostatic expansion valve (TXV)
4 Evaporator matrix
5 Evaporator temperature sensor

The sub-cooled liquid refrigerant passes from the outlet of the condenser through a pipe to a thermostatic expansion 
valve (TXV) situated at the engine compartment bulkhead. The TXV connects to the evaporator unit mounted inside 
the air inlet and blower motor casing in the vehicle cabin.

The thermostatic expansion valve meters the flow of refrigerant into the evaporator, to match the refrigerant flow with 
the heat load of the air passing through the evaporator matrix.

The thermostatic expansion valve (block valve) incorporates a restrictor which converts the liquid refrigerant into a 
low temperature, low pressure liquid vapour mixture (fine spray). The valve has an internally located temperature 
sensing bulb for precise control of superheat. If high temperatures are sensed, the valve opens wider and vice versa.